Hi,
I'm hoping someone an help me, I have been knitting for a while, mainly scarf and shawls but am attempting my first cardigan.
I'm setting raglan sleeves and the instructions are:

K1, s1, K1 psso, knit to last 3 sts, k2tog, K1
This row sets raglan shaping
Dec 1 st as set at each end of next and 2 (1:0:0:0:0:0:0) foll 4th rows then on every foll alt row to 23 (23:23:23:25:25:25:25) sts.
Work 1 row with RS facing for next row.

Questions
The next row is a purl, but the 'as set' is on the knit row so does it mean the next RS row.
I am making 6th size, does that mean I have to do 4 rows (2 sets of 4 without decreasing before going onto the alternate shaping or ignore that instruction as I have a 0 next to the size?

Any help gratefully received I'm loving this knit but the pattern is defeating me!

Yes, the pattern not really clear but the raglan shaping should be on the knit, RS rows. The WS rows are purl all the sts.
For the 6th size the instuction becomes:
Dec 1 st as set at each end of next and every foll alt row to 23 (23:23:23:25:25:25:25) sts.
Work 1 row with RS facing for next row.
So yes, ignore the instuctions where you have a 0 for your size.

Since the instruction for the 6th size is '0', you skip this one and go on to the next one which is to inc on every other row. You don't knit 4 rows, then inc, just ignore that instruction and go directly to increasing every other row.